diff --git a/config/Moz/Milestone.pm b/config/Moz/Milestone.pm
new file mode 100755
index 00000000000..8dd1449cbc4
--- /dev/null
+++ b/config/Moz/Milestone.pm
@@ -0,0 +1,232 @@
+#!/usr/bin/perl -w
+# ***** BEGIN LICENSE BLOCK *****
+# Version: MPL 1.1/GPL 2.0/LGPL 2.1
+#
+# The contents of this file are subject to the Mozilla Public License Version
+# 1.1 (the "License"); you may not use this file except in compliance with
+# the License. You may obtain a copy of the License at
+# http://www.mozilla.org/MPL/
+#
+# Software distributed under the License is distributed on an "AS IS" basis,
+# WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+# for the specific language governing rights and limitations under the
+# License.
+#
+# The Original Code is the Win32 Version System.
+#
+# The Initial Developer of the Original Code is Netscape Communications Corporation
+# Portions created by the Initial Developer are Copyright (C) 2002
+# the Initial Developer. All Rights Reserved.
+#
+# Contributor(s):
+#
+# Alternatively, the contents of this file may be used under the terms of
+# either the GNU General Public License Version 2 or later (the "GPL"), or
+# the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+# in which case the provisions of the GPL or the LGPL are applicable instead
+# of those above. If you wish to allow use of your version of this file only
+# under the terms of either the GPL or the LGPL, and not to allow others to
+# use your version of this file under the terms of the MPL, indicate your
+# decision by deleting the provisions above and replace them with the notice
+# and other provisions required by the GPL or the LGPL. If you do not delete
+# the provisions above, a recipient may use your version of this file under
+# the terms of any one of the MPL, the GPL or the LGPL.
+#
+# ***** END LICENSE BLOCK *****
+
+package Moz::Milestone;
+use strict;
+
+use vars qw($officialMilestone
+            $milestone);
+
+local $Moz::Milestone::milestone;
+local $Moz::Milestone::officialMilestone;
+
+#
+# Usage:  getOfficialMilestone($milestoneFile)
+# Returns full milestone (x.x.x.x[ab12pre+])
+#
+sub getOfficialMilestone($) {
+  my $mfile = $_[0];
+  open(FILE,"$mfile") ||
+    die ("Can't open $mfile for reading!");
+
+  my $num = <FILE>;
+  while($num =~ /^\s*#/ || $num !~ /^\d/) {
+      $num = <FILE>;
+  }
+
+  close(FILE);
+  if ($num !~ /^\d/) { return; }
+  chomp($num);
+  # Remove extra ^M caused by using dos-mode line-endings
+  chop $num if (substr($num, -1, 1) eq "\r");
+  $Moz::Milestone::officialMilestone = $num;
+  $Moz::Milestone::milestone = &getMilestoneNum;
+  return $num;
+}
+
+#
+# Usage: getMilestoneNum($num)
+# Returns: milestone without a + if it exists.
+#
+sub getMilestoneNum {
+  if (defined($Moz::Milestone::milestone)) {
+    return $Moz::Milestone::milestone;
+  }
+
+  if (defined($Moz::Milestone::officialMilestone)) {
+    $Moz::Milestone::milestone = $Moz::Milestone::officialMilestone;
+  } else {
+    $Moz::Milestone::milestone = $_[0];
+  }
+
+  if ($Moz::Milestone::milestone =~ /\+$/) {    # for x.x.x+, strip off the +
+    $Moz::Milestone::milestone =~ s/\+$//;
+  }
+
+  return $Moz::Milestone::milestone;
+}
+
+#
+# Usage: getMilestoneQualifier($num)
+# Returns: + if it exists.
+#
+sub getMilestoneQualifier {
+  my $milestoneQualifier;
+  if (defined($Moz::Milestone::officialMilestone)) {
+    $milestoneQualifier = $Moz::Milestone::officialMilestone;
+  } else {
+    $milestoneQualifier = $_[0];
+  }
+
+  if ($milestoneQualifier =~ /\+$/) {
+    return "+";
+  }
+}
+
+sub getMilestoneMajor {
+  my $milestoneMajor;
+  if (defined($Moz::Milestone::milestone)) {
+    $milestoneMajor = $Moz::Milestone::milestone;
+  } else {
+    $milestoneMajor = $_[0];
+  }
+  my @parts = split(/\./,$milestoneMajor);
+  return $parts[0];
+}
+
+sub getMilestoneMinor {
+  my $milestoneMinor;
+  if (defined($Moz::Milestone::milestone)) {
+    $milestoneMinor = $Moz::Milestone::milestone;
+  } else {
+    $milestoneMinor = $_[0];
+  }
+  my @parts = split(/\./,$milestoneMinor);
+
+  if ($#parts < 1 ) { return 0; }
+  return $parts[1];
+}
+
+sub getMilestoneMini {
+  my $milestoneMini;
+  if (defined($Moz::Milestone::milestone)) {
+    $milestoneMini = $Moz::Milestone::milestone;
+  } else {
+    $milestoneMini = $_[0];
+  }
+  my @parts = split(/\./,$milestoneMini);
+
+  if ($#parts < 2 ) { return 0; }
+  return $parts[2];
+}
+
+sub getMilestoneMicro {
+  my $milestoneMicro;
+  if (defined($Moz::Milestone::milestone)) {
+    $milestoneMicro = $Moz::Milestone::milestone;
+  } else {
+    $milestoneMicro = $_[0];
+  }
+  my @parts = split(/\./,$milestoneMicro);
+
+  if ($#parts < 3 ) { return 0; }
+  return $parts[3];
+}
+
+sub getMilestoneAB {
+  my $milestoneAB;
+  if (defined($Moz::Milestone::milestone)) {
+    $milestoneAB = $Moz::Milestone::milestone;
+  } else {
+    $milestoneAB = $_[0];
+  }
+  
+  if ($milestoneAB =~ /a/) { return "alpha"; }
+  if ($milestoneAB =~ /b/) { return "beta"; }
+  return "final";
+}
+
+#
+# build_file($template_file,$output_file)
+#
+sub build_file($$) {
+  my @FILE;
+  my @MILESTONE_PARTS;
+  my $MINI_VERSION = 0;
+  my $MICRO_VERSION = 0;
+  my $OFFICIAL = 0;
+  my $QUALIFIER = "";
+
+  if (!defined($Moz::Milestone::milestone)) { die("$0: no milestone file set!\n"); }
+  @MILESTONE_PARTS = split(/\./, &getMilestoneNum);
+  if ($#MILESTONE_PARTS >= 2) {
+    $MINI_VERSION = 1;
+  } else {
+    $MILESTONE_PARTS[2] = 0;
+  }
+  if ($#MILESTONE_PARTS >= 3) {
+    $MICRO_VERSION = 1;
+  } else {
+    $MILESTONE_PARTS[3] = 0;
+  }
+  if (! &getMilestoneQualifier) {
+    $OFFICIAL = 1;
+  } else {
+    $QUALIFIER = "+";
+  }
+
+  if (-e $_[0]) {
+    open(FILE, "$_[0]") || die("$0: Can't open $_[0] for reading!\n");
+    @FILE = <FILE>;
+    close(FILE);
+
+    open(FILE, ">$_[1]") || die("$0: Can't open $_[1] for writing!\n");
+
+    #
+    # There will be more of these based on what we need for files.
+    #
+    foreach(@FILE) {
+      s/__MOZ_MAJOR_VERSION__/$MILESTONE_PARTS[0]/g;
+      s/__MOZ_MINOR_VERSION__/$MILESTONE_PARTS[1]/g;
+      s/__MOZ_MINI_VERSION__/$MILESTONE_PARTS[2]/g;
+      s/__MOZ_MICRO_VERSION__/$MILESTONE_PARTS[3]/g;
+      if ($MINI_VERSION) {
+        s/__MOZ_OPTIONAL_MINI_VERSION__/.$MILESTONE_PARTS[2]/g;
+      }
+      if ($MICRO_VERSION) {
+        s/__MOZ_OPTIONAL_MICRO_VERSION__/.$MILESTONE_PARTS[3]/g;
+      }
+
+      print FILE $_;
+    }
+    close(FILE);
+  } else {
+    die("$0: $_[0] doesn't exist for autoversioning!\n");
+  }
+
+}
+
+1;
diff --git a/config/version_win.pl b/config/version_win.pl
index 3c0f00c70a3..73c7b0f5569 100755
--- a/config/version_win.pl
+++ b/config/version_win.pl
@@ -138,7 +138,6 @@ if ($bits eq "16") { $fileos="VOS__WINDOWS16"; }
 my $bufferstr="    ";
 
 my $MILESTONE_FILE = "$topsrcdir/config/milestone.txt";
-my $BUILDID_FILE = "$depth/config/build_number";
 
 #Read module.ver file
 #Version file overrides for WIN32:
@@ -243,17 +242,7 @@ if ($official eq "1") {
 
 	}
 
-	my ($buildid, $buildid_hi, $buildid_lo);
-	open(NUMBER, "<$BUILDID_FILE") || die "No build number file\n";
-	while ( <NUMBER> ) { $buildid = $_ }
-	close (NUMBER);
-	$buildid =~ s/^\s*(.*)\s*$/$1/;
-	$buildid_hi = substr($buildid, 0, 5);
-	$buildid_lo = substr($buildid, 5);
-
-	$mfversion = $mpversion = "$milestone: $buildid";
-	my @pvarray = split(',', $productversion);
-	$fileversion = "$pvarray[0],$pvarray[1],$buildid_hi,$buildid_lo";
+	$mfversion = $mpversion = "$milestone";
 }
 
 my $copyright = "License: MPL 1.1/GPL 2.0/LGPL 2.1";
@@ -390,7 +379,6 @@ print RCFILE qq{
 //
 
 1 VERSIONINFO
- FILEVERSION $fileversion
  PRODUCTVERSION $productversion
  FILEFLAGSMASK 0x3fL
  FILEFLAGS $fileflags